Arnold the Pit Bull Dog from Tiny Toons Adventures.
Dudley is similar to Po from the Kung Fu Panda franchise: Both are clumsy dimwits who get accepted into a group (Dudley into T.U.F.F. and Po into the Furious Five and as the Dragon Warrior). As well, their partners doesn't accept them at first, but they eventually grow to like them. Another similarity is that Dudley and Po both wear the same exact clothes as they did before getting accepted.
Although Dudley doesn't usually wear anything more than his shirt, a recurring joke is that the fur on his lower body works as a pair of pants, even to the point that he wears underwear underneath them in Mom-A-Geddon.
Dudley shares some personality traits with (if not a first name) with Dudley Do-Right. He has eyes of blue, is a good crime fighter, and can be confused or silly at times.
Dudley has fallen in love with villains twice. The first time was in Puppy Love when the The Chameleon transformed into Fifi Oui Oui with Dudley not knowing it was The Chameleon in disguise. The second time was in Love Bird when Dudley fell in love with Bird Brain due to his love gun.
Dudley also has the same personality and skills as Maxwell Smart from Get Smart.
Dudley was originally going to wear a collar, as seen in the clip art, but the creators did not feel that it was right for him.
Along many episodes, Dudley appears to be very naive.
Dudley is shown to be afraid of thunder in the episode Thunder Dog. This fear is a reference to his Get Smart counterpart, Maxwell Smart, in the episode Witness Of Persecution. Ironically, most dogs are known to be afraid of thunder, most likely due their exceptional sense of hearing.
As a dog, Dudley has a bad habit of chewing the furniture. Especially in the episode Booby Trap.
It is shown in the episode The Curse of King Mutt that Dudley has a digging mania.
He is shown to be superstitious since, in Thunder Dog, he believed Kitty when she told him that the collar removes fear.
It's said in Cold Fish that Dudley lives with his mom.
Ignoring his excellent senses of hearing and smell, in the episode The Curse of King Mutt Dudley seems unable to differentiate Snaptrap, Bird Brain and the uncamouflaged Chameleon from an ancient mummy.
He seems to display an interest in the performing arts as shown in The Rat Pack.
Dudley has blue eyes, just like Timmy Turner and Danny Fenton/Phantom, the two main characters of Butch Hartman's other TV series (The Fairly Oddparents and Danny Phantom).
In Booby Trap Dudley chewed the furniture at T.U.F.F. and the wicker bars at the jail. It is a common puppy (young dog) trait to chew on things.
In Snap Dad it is revealed that Dudley doesn't have an uncle, this suggest that both Peg and Dudley's unknown father were both an only-child or had only single sisters. However, Dudley may have an unknown uncle seeing as he does not know who his father is.
In Snapnapped, while in the conference room, Dudley is playing a Game Pup, a parody of Game Boy.
In The Fairly OddParents episode, Timmy's Secret Wish, Dudley can be seen in the toy wave with Timmy Turner (only with white ears instead of black).
In The Fairly OddParents episode "Meet the Odd Parents", Vicky's head (a series-long sight gag in the title sequence which changes every episode) is changed into that of Dudley Puppy's.
Ignoring his adult age, Dudley proves to be completely irresponsible, especially in the episode Frisky Business when he seems to be completely helpless without the acre and orders his mother.
It was revealed in Big Dog on Campus that when Dudley was in high school, he had zits, braces, was skinny, wore glasses, and was an outcast.
In the Original Stud Puppy Poster, Dudley was shown to be more ripped and have the dog collar he was supposedly going to wear for the start of the series.
Butch mentioned on an interview, that even before the start of the The Fairly OddParents, he always drew a dog in a black shirt, but didn't know where to put him, and now years later, he is revealed to be Dudley Puppy.
In Nicktoons MLB, Dudley jumps in the air when he hits a home run.
Dudley waves to the fans when he makes a great catch in Nicktoons MLB.
Dudley is Butch Hartman's first character, however, he is the latest of his cartoon characters to be featured on a TV series, it was also revealed his original name was Dudley Dog but Butch Hartman later changed it to Dudley Puppy.
In Diary of a Mad Cat, it is shown that whenever Dudley says "exactly", he chews his butt.
As seen in Dudley Do-Wrong there are no girls allowed in his bedroom (except for his mother).
Apparently Dudley isn't ready for marriage yet, this is evident in Dog Tired. However in Puppy Love, he jumps at the chance to marrying Fifi Oui Oui when he has it (The Chameleon in disguise, even though Dudley didn't know it).
Dudley doesn't wear pants because he can't see his tail. His tail shows how he is feeling.
Even though Quacky the Duck has tried to destroy Dudley and Kitty several times, Dudley still places his trust in him. In Quack in the Box, he once again flaunts over the diabolical duck at the opening of his new restaurant. He can also be seen later in the episode as a current member of the Quacky the Duck Fan Club where he admits he would "shoot missiles from a car and drop bombs from a helicopter to prove my love for Quacky!". Later on, Dudley unintentionally aids in the destruction of two restaurants; Argh-By's and Taco Bull when given a set of evil robotic toys from Quacky himself who are used to frame Dudley for a series of crimes so that Quacky can destroy his restaurant's competition without being thrown in jail. He was also still enthusiastic to play a character in Quacky's movie in Lights, Camera, Quacktion.
In the episode Top Dog, Dudley nearly kills the Chief twice by wearing a flea collar.
He makes bad lasagna, as shown in Top Dog. However, this makes no sense considering the fact that he can make his own pasta sauce plus in Law and Odor he criticized Keswick's spaghetti. (Since this shows he has an understanding of things like spices, vegetables, and cooking).
In Freaky Spy-Day it's shown that he sometimes jumps into a room whenever entering it. (However, it isn't revealed if he says "Let's go!" when doing it like in certain Nickelodeon promos).
In Top Dog Dudley is the only one who understood how to improve the Frisking Robot to everyone's dismay. He thought of adding more arms to make it frisk better. This shows that he has some basic intelligence which may grow later in the series.
He bears a little resemblance to his mother, this may give a clue on how Dudley's father may look like.
In Candy Cane-ine it's shown that Dudley's one true fear is that of bugs yet he isn't afraid of The Chief who is a flea. (In Thunder Dog it was shown that Dudley was afraid of thunder and the dentist, but he overcame this fear of thunder with the help of Kitty and in Lie Like a Dog, a later episode, he was able to confront his dentist, Dr. Fineberg, perfectly.)
He spends his pants money on candy as revealed in Dog House.
In Quacky Birthday has revealed his month of own birthday but still yet unknown in which day was born.
In Purr-fect Partners he had a cape, it is unknown if he still has it or sold it offscreen.
None of the other characters appeared in The Fairly Oddparents so its possible that Dudley is Butch Hartman's favorite character.
Dudley's behavior is the same as Sparky from The Fairly Oddparents.